// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/base/host_mapping_rules.h"

#include "base/logging.h"
#include "base/strings/pattern.h"
#include "base/strings/string_split.h"
#include "base/strings/string_tokenizer.h"
#include "base/strings/string_util.h"
#include "net/base/host_port_pair.h"
#include "net/base/url_util.h"

namespace net {

struct HostMappingRules::MapRule {
    MapRule()
        : replacement_port(-1)
    {
    }

    std::string hostname_pattern;
    std::string replacement_hostname;
    int replacement_port;
};

struct HostMappingRules::ExclusionRule {
    std::string hostname_pattern;
};

HostMappingRules::HostMappingRules() { }

HostMappingRules::~HostMappingRules() { }

bool HostMappingRules::RewriteHost(HostPortPair* host_port) const
{
    // Check if the hostname was excluded.
    for (ExclusionRuleList::const_iterator it = exclusion_rules_.begin();
         it != exclusion_rules_.end(); ++it) {
        const ExclusionRule& rule = *it;
        if (base::MatchPattern(host_port->host(), rule.hostname_pattern))
            return false;
    }

    // Check if the hostname was remapped.
    for (MapRuleList::const_iterator it = map_rules_.begin();
         it != map_rules_.end(); ++it) {
        const MapRule& rule = *it;

        // The rule's hostname_pattern will be something like:
        //     www.foo.com
        //     *.foo.com
        //     www.foo.com:1234
        //     *.foo.com:1234
        // First, we'll check for a match just on hostname.
        // If that fails, we'll check for a match with both hostname and port.
        if (!base::MatchPattern(host_port->host(), rule.hostname_pattern)) {
            std::string host_port_string = host_port->ToString();
            if (!base::MatchPattern(host_port_string, rule.hostname_pattern))
                continue; // This rule doesn't apply.
        }

        host_port->set_host(rule.replacement_hostname);
        if (rule.replacement_port != -1)
            host_port->set_port(static_cast<uint16_t>(rule.replacement_port));
        return true;
    }

    return false;
}

bool HostMappingRules::AddRuleFromString(const std::string& rule_string)
{
    std::vector<std::string> parts = base::SplitString(base::TrimWhitespaceASCII(rule_string, base::TRIM_ALL),
        " ", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);

    // Test for EXCLUSION rule.
    if (parts.size() == 2 && base::LowerCaseEqualsASCII(parts[0], "exclude")) {
        ExclusionRule rule;
        rule.hostname_pattern = base::ToLowerASCII(parts[1]);
        exclusion_rules_.push_back(rule);
        return true;
    }

    // Test for MAP rule.
    if (parts.size() == 3 && base::LowerCaseEqualsASCII(parts[0], "map")) {
        MapRule rule;
        rule.hostname_pattern = base::ToLowerASCII(parts[1]);

        if (!ParseHostAndPort(parts[2], &rule.replacement_hostname,
                &rule.replacement_port)) {
            return false; // Failed parsing the hostname/port.
        }

        map_rules_.push_back(rule);
        return true;
    }

    return false;
}

void HostMappingRules::SetRulesFromString(const std::string& rules_string)
{
    exclusion_rules_.clear();
    map_rules_.clear();

    base::StringTokenizer rules(rules_string, ",");
    while (rules.GetNext()) {
        bool ok = AddRuleFromString(rules.token());
        LOG_IF(ERROR, !ok) << "Failed parsing rule: " << rules.token();
    }
}

} // namespace net
